1. Field of the Invention
The present invention relates to a variable operation angle mechanism which varies a valve operation angle of an intake valve and, to an apparatus for and a method of controlling an engine which is provided with the variable operation angle mechanism.
2. Description of the Related Art
Japanese Laid-open (Kokai) Patent Application Publication No. 2005-291014 discloses a variable operation angle mechanism suitable for use in an engine to vary a center phase of a valve operation angle in an advance direction in response to a decrease in the valve operation angle of an intake valve.
Although this Patent publication fails to specifically disclose a change amount of the center phase of the valve operation angle relative to a variation in the valve operation angle, it is to be understood that the change amount of the central phase of the valve operation angle highly affects a response at a transient operation of the engine, a fuel consumption at the transient operation, and an engine-stall resistance.
Thus, if the variation characteristic of the center phase of the valve operation angle relative to the change amount thereof is improper, the engine performance during the transient operation thereof might be greatly degraded.